问题
选择题
若复数z=(a2-5)+(a+
|
答案
复数z=(a2-5)+(a+
)i为纯虚数，则有5
，解得a=a2-5=0 a+
≠05
．5
则
=a+i2011 1+
i5
=
+ i502×4+35 1+ 5i
=
+(-i)5 1+ 5i
=(
-i)(1-5
)5i (1+
) (1-5i
)5i
=-i．-6i 6
故选D．
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